Piston



P. BUTCHER @am @9 E929@ PISTON Filed Feb. 21. 1928 2 Sheets-Sheet lPatented 3, 1929 Nrrao PERUY ld'UJiCHEiR, 0F JACKSONVILLE, FLRIDA;

Application med Februaryl, 192B. @arial 11o. 255,971.

piston body having an expanding shell with means in the form of a Wedgering that is interposed between the body and shell for maintaining theparts of the piston in sealin or fluid-tight engagement.

Another object is to provide a piston composed of a body and a sectionalshell with means in the form of expansible coil-springs for pressing'theadjacent surfaces of the piston parts together so as to prevent leakagetherebetween.

Another object is to produce an efficient, strong and durable pistonwhich may be economically constructed and operated.

Other objects and advantages will hereinafter appear.

The views of the drawings are:

Figure 1 is an elevation, partially in vertical longitudinal section ofa piston constructed according to the preferred embodiment of -myinvention;

Fi 2 is a vertical longitudinal section of the piston body shown in`elevation in Fig. 1;

Fig. 3 is a perspective' of the ring which is interposed between thepistonbody and the 4surrounding shell;

Fig. 4-is a perspective of the piston, parts being in section; i

Fig. 5 is a detail vertical longitudinal section, illustrating amodified form of my invention;

Fig. 6 is a vertical longitudinal section through a piston valve showingthe application of my invention thereto;

Fig. 7 is a perspective of one of the shell sections shown in ig. 6;

Fig. 8 is a pers ective of one ofthe piston bodies shown in ig. 6; and

Fig. 9 is a vertical longitudinal section of another piston valveillustrating a further form of the invention.

Referring to the drawings, and especially to Figs. 1 to 4 inclusive, thepiston comprises a cylindrical bod?r 1 having a series of beveled faces2, 3 and 4 ormed on its exterior. The

faces provide a plurality of bearing surfaces,

the purpose of which will be hereinafter apparent. The arrangement ofthe faces 2 and 3 should be such as to provide an annular rib 5 near thetop of the body 1. The lower portion of the body 1 is reduced 55 1ndiameter adistance substantially equal to the depth of the rib 5, so asto provide an annular horizontal shoulder 6.

The body 1 is hollow and it has inwardly projecting bosses 7 for thereception of a e0 wrist pin (not shown).

Surroundin the sides of the body 1 is a shell compose of a plurality ofsections 8 (in the present instance two).

The shell sections define a cylindrical struce5 ture so thatA the pistonwill iit snugly in a cylinder.

The interior of the shell sections are frme'd with beveled portions 9,10, 11, 12 and The surfaces 9 and 10 provide an annular groove havingbeveled surfaces that coact with the surfaces 2 and 3 of the body 1.

The opposed ed es of the shell sections are preferably forme withalternate notches 14 I5 l and projections 15 so that they fit one intothe other to provide labyrinthine joints extending longitudinally of thepiston.

When the shell sections are assembled on the body 1 there is an annularspace below so the shoulder 6, the bottom of this space being closed bythe beveled surface 12.

A plurality of recesses 16 are formed in the shoulder 6 of the body 1(in the present nstance three). Y

The recesses 16 have an irre lar configuration so as to receive bosses 1of a ring 18 and an expansible spring 19.

One portion of the recesses 16 is rectangular, having a vertical wall 20and a horizontal 90 Wall 21. v

The remainder of the recesses include an. u wardly inclined surface 22that terminates a ove the wall 21 in a relatively short horizontalsurface 23. 9

The surface 23 is connected to the wall 21 by a vertical surface 24. Y

A notch is thus formed in the u per wall of the recesses 16 for apurpose to hereinafter more fully described.

cated at 25. This surface of the ring bears against the surface 12 ofthe shell sections,

' and in this way the ringvwill be supported by f portion of therecesses the shell.

The bosses 17 are adapted to fit within the 16 defined by the surfaces22, 23 and 24. Therefore, the bosses have correspondingly formedsurfaces 26, 27 and 28 for vrespectively coacting with the surfaces 22,23 and 24.

The springs 19 aremounted in the portion of each of the recesses 16defined by the vertical wall 20 and horizontal wall 21. One end of thespring abuts the wall 20, while its opposite end abuts the vertical face28 of the bosses 17.

The springs 19 tend to. move the ring 18 partly around the body in arotating manner.

This action will provide a fluid tight engagement of the beveledsurfaces of the body l and the corresponding surfaces of the shellsections 8, the ring v18 functioning as means for wedgingthe partstogether, regardless of piston speed or inertia which might causemovement of the shell sections if the ring was not employed.Furthermore, the inclined' surfaces 26 of the bosses will cause equalmovement of the ring downwards of the piston body thereby positivelysealing the coacting surfaces. This action of the wedge ring is limitedto the outward `movement of the shell sections to the limit oftheirvexpansion within the walls of the cylinder.

A slightlymodiied application of the inj vention is shown by Fig. 5,wherein the bosses on the ring 18 are eliminated,and vertically disosedsprings substituted therefor.

li-)eferring to Fig. 5 the shoulder 6 of the body 1 is formedwith'vertical recesses 31 in which are disposed expansible coilsprings'32l (only a single recess and spring being shown) The springsbear against the upper horizontal face of the ring 18 and thus force thebeveled face of the ring into contact with the surface 12 of the shellsections. In other respects the construction is similar to thatdescribed features of pistons or plungers constructed as abovedeheretofore described.

Obviously it-is immaterial just what type of prime mover or engineutilizes the above my invention, since scribed may be employedadvantageously in steam engines of the double or single acting type, aswell as in uniflow engines, pumps, etc. Moreover, without departing frommy invention, I may use the construction described i -n connection withpiston valves, in either of the ways suggested in Figs. 6 to. 9,inclusive. eferring now to Figs. 6 to 8, inclusive, the piston valve isdesigned for use in a chest or casing in which fluid underv pressure isadmitted to the centra-l portion of the valve. The piston includes abody 35 and cylindrical heads 36. y

lar to the coacting beveled faces of the body,

and shell sections.

In order to prevent the shell sections from rotating around the heads36, a pin 44 carried by the shell sections, is passed through an opening45 formed in the heads 36.

A cotter pin 46is passed through the extremity of the pin 44 lyingwithin the heads 36 to retain the shell sections and springs in positionwhen the piston passes the valve, and to prevent disassembly ofitheparts when the piston is not mounted in its chamber.

It is understood, of course, that the opposed edges of the shellsections are formed with alternatenotches 47 and projections 48 so thatthey fit one into the other to provide labyrinthine joints, aspreviously described.

In'the form of the invention shown in Fig. 9, the head 50 of a pistonvalve is formed withannular ribs 51 and 52.

The rib 51 has a beveled side 53, while the rib 52 has a'beveled side54, such beveled surfaces being opposed to each other to form a groove55.

The side of the rib 52 opposite to the side 54 providesa verticalshoulder 56.

A sectional expanding shell 57 encircles the head 50. This shell has an.annular rib 58 with beveled sides for c'oacting with the sides of thegroove of the head 50. i

"Near one end of the shellthere is. a beveled surface 59 which is,when`the shell is assembled on to the head, disposed at a distance fromthe shoulder 56, thereby providing an annular space for a wedge ring 60.

The ring 60 has a beveled surface 61 for coacting with the surface 59 ofthe shell sections.

' The ring 60 is provided with a plurality of recesses 62 (only onebeing shown), Similai" recesses 63 are formed in the shoulder of thehead 50.

When the shell sections are assembled on the head, the recesses 62 and63 are alined so as to receive expansible coil springs64. The purpose ofthe springs 64 is to force the beveled face of the ring 60 against thecorrespondingly formed surface of the shell sections so as to seal thejoints between the coacting surfaces of the piston valve body in themanner heretofore described.

With the above described arrangement of parts leakage past the piston orpiston valve in either direction will 'be effectually prevented, as wellas leakage between the body and the shell sections or through the jointsbetween the adjacent edges of the shell sec-l tions, and the true centerline of the body is maintained with the true center line of the cylinderbore, regardless of wear of the shell sections or difference inexpansion between tbe shell'V sections 'and the body. Further more, thewed e ring will prevent side slap of `tbe body, as will be readilyunderstood.

"fhe invention claimed v1s l.. The combination in-a piston, of a bodyhaving a plurality of beveled surfaces there on, an expanding shellmounted on the said body, said shell being composed of a pluralit ofindependent segmental sections and inclu i ing inclined surfacescoacting \with the beveled surfaces of the body, the bottom of the shellextending beyond the bottom of the said vbody and being provided with aninwardly projecting rib having an upper beveled surface disposed inspaced relation to the bottom of the said body, and a ring interposedbetween the said rib and the bottom of the said body, said ring havingsurfaces correspondingly formed to the adjacent surfaces of the saidbody and the said shell sections. 2. rflue combination in a piston, of abody having a plurality of beveled surfaces thereon, an expanding shellmounted' on the said body, said shell being composed of a plurality ofindependent segmental sections and including inclined surfaces coactingwith the beveled surfaces of the body, the bottom of the shell extendingbeyond the bottom of the mi 'said body and being provided with aninwardly projecting rib having an upper beveled surface disposed inspaced relation to the bottom of vthe said body, a lurality of 1recessesformed in the bottom o the body, and a ring interposed between the saidrib and the bottom of the said body and having bossesprojecting into thesaid recesses, said ring having surfaces correspondingly formed to theadjacent surfaces of the said body and the said shell sections. c 3. Thecombination in a piston, of a body having a plurality of beveledsurfaces thereon,.an expanding shell mounted on the said body, saidshell being composed of a plurality of mdependent segmental sections andincluding inclined surfaces coacting with the beveled surfaces of t-hebody, the bottom of the shell extending beyond the bottom of the saidbody and being rovided with an inwardly projecting rib aving an upperbeveled surface disposed in spaced relation to the bottom of the saidbody, a plurality of recesses formed in the bottom of the body, saidrecesses having an inclined surface and an angular surface, a ringinterposed between the said rib and the bottom of the said body, bossesprojecting upwardly from the ringand having inclined surfaces forcoact-ing with the inclined surfaces of the said recesses, said 05 ringhaving surfaces correspondingly formed dll to the adjacent surfaces ofthe said body and the said shell sections, and expansible coil springsmounted in the portions of the recesses having the said angular surfacesfor the purpose of exerting tension against the ends of the said bosses.4. The combination in a piston of a body having exterior beveled bearingsurfaces, a shell composed of a plurality of segmental sections formedto cooperate with the bearing surfaces of the said body, andsubstantially enclosing it, a shoulder formed in the body,

near one end thereof, a beveled rib formed on the shell and disposed inspaced relation`\ to the said shoulder, a ring interposed in the spacebetween the said rib and the said shoulder, said ring having a beveledsurface bearing against the adjacent surface of thesaid rib, and tensionmeans between the said ring and the said shoulder` 85 5. The combinationwith a piston body, of a sectional shell movable into an expandedposition, said shell having a beveled portion, a circularly movablewedging member carried by said body provided with a beveled portionadapted to coact With the beveled portion of said shell, and resilientmeans whereby a rotary movement of said wedging member may beaccompanied with an axial movement, so that said shell may be moved intoan expanded position.

PERCY BUTCHER.

